Placement of musical notes in time relative to one another is a foundational element of music and is typically referred to as timing and rhythm. Executing groupings of notes with accurate relative timing is vital for musicians to be able to start together and end together without speeding up, slowing down, or otherwise getting separated during the course of a performance. Musicians have, for thousands of years, sought ways to improve their timing and rhythmic skills.
In 1812, Dietrik Winkel found that a double-weighted pendulum (i.e., a pendulum having a weight on each side of a pivot) would swing as slowly as 25 swings per minute, even when the pendulum was made of short length. Johann Nepenuk Maelzel appropriated Winkel's idea and, in 1816, started manufacturing “Maelzel's Metronome”, which featured a sliding weight used for pendulum swing-rate adjustment and a mechanism to generate an audible click used as a primary beat. Maelzel's Metronome was widely used as a timing reference device for musicians.
Since Maelzel's design of 1816, metronomes have remained largely unchanged. They continue to be a primary tool used by musicians to improve their timing skills. The standard method of use is to set a click rate and then play along with the metronome while trying to listen for timing differences between clicks generated by the metronome and a sound of one's own instrument's moment of attack. These dual tasks are often difficult to perform. They are: 1) playing the sound on the musical instrument; and 2) listening for and recognizing timing differences between the two sounds by ear while planning for and preparing to play the next sound on the instrument. The difficulty of determining which of the two sounds occurs first is compounded when the two sounds are very close together in time. This complex split-attention skill must be developed if a musician is to improve his or her timing skills using a metronome.
Musicians also must develop dynamic control, which typically means their ability to control the relative loudness and softness of their sounds. However, there is no device available whose purpose is to measure and report the relative dynamic level of the user's sounds to the user.